Existing microelectronic device packages typically include a microelectronic die attached to a support member, such as a printed circuit board. Bond-pads or other terminals on the die are electrically connected to corresponding terminals on the support member, for example, with solder balls or wires. The connection between the die and the support member can be protected by encapsulating the die to form a device package. The package can then be electrically connected to other microelectronic devices or circuits in many types of consumer or industrial electronic products.
Manufacturers are under continuous pressure to reduce the size of the electronic products. Accordingly, microelectronic die manufacturers seek to reduce the size of the packaged dies incorporated into the electronic products. The height of the packaged dies is often reduced by grinding the back side of the wafer to thin the dies before singulating the wafer and encapsulating the dies. One drawback with this approach, however, is that thin wafers are extremely fragile and therefore difficult to handle after backgrinding.
One approach for addressing this drawback is to attach a relatively thick wafer support to the wafer for the grinding process to ensure survival of the wafer as well as to facilitate subsequent handling of the wafer for further processing. One system, for example, includes applying or laminating a generally flowable material onto an active side of the wafer and then curing the material to a desired rigidity to form the wafer support. After backgrinding, the thinned wafer is attached to a vacuum chuck and the wafer (and attached wafer support) are completely immersed into a solvent bath to dissolve or otherwise remove the wafer support. The wafer is then flipped and mounted on a dicing frame with the active side of the wafer facing downward, after which the wafer is singulated and the individual dies are removed from the dicing frame with a conventional pick-and-place apparatus. In several instances, the wafer can be mounted to the dicing frame before removal of the wafer support.
One drawback with the foregoing approach is that the thinned wafer must undergo a number of additional processing steps after the wafer support is removed. In some situations, for example, the thinned wafer (without any support) must be transferred from the vacuum chuck to the dicing frame before singulation. The thinned wafer is highly susceptible to damage and/or breakage during this transfer process. In situations where the wafer support is not removed until after the wafer is attached to the dicing frame, the wafer must still undergo singulation without any support. Moreover, the thinned, singulated dies are extremely fragile and a number of dies can be damaged and/or broken during removal from the dicing frame and subsequent handling.
Another approach for addressing this drawback is to attach a generally rigid, glass support member to the wafer to support the wafer during the grinding process and subsequent handling. The support member can be attached to the wafer using, for example, a light-activated adhesive or another suitable adhesive material. In several instances, a plurality of holes can be formed completely through the support member to expose a portion of the wafer. These holes are used to help facilitate removal of the adhesive material from the wafer. After backgrinding, the wafer support member is removed and the resulting thin wafer is ready for singulation and further processing.
This system, however, also has several drawbacks. One drawback is that the wafer support is generally removed before singulation because it is extremely difficult to cut through the glass support member during singulation. The holes through the support member further complicate the singulation process and make singulation with the glass support attached to the wafer impracticable. Accordingly, the thinned wafer must undergo singulation without any support. Another drawback with this system is that many adhesive materials can be difficult to remove from the wafer after processing. The removal process, for example, may require a number of additional processing steps involving heat and/or solvents. Accordingly, the wafer can be vulnerable to damage, contamination, and/or breakage during removal of the adhesive materials. Thus, there is a need to improve the handling of microfeature workpieces during processing.